Studies on stem rot of Groundnut (Arachis hypogaea L.) and its management
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Date
2018-06-06
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OUAT,Bhubaneswar
Abstract
Seed and soil borne diseases have been recognized as major constraint limiting groundnut production. Among the soil borne diseases the stem rot disease incited by Sclerotium rolfsii Sacc. assume major threat to farmers of Odisha resulting seedling mortality and ultimately causing reduction in pod yield. Hence the present investigation has been undertaken in the title “Studies on stem rot of Groundnut (Arachis hypogaea L.)and its management” aimed at monitoring and survey of groundnut diseases in east and south east coastal tracts of Odisha, influence of weather parameters on stem rot disease incidence, in vitro bioassay with biocontrol agents, fungicides and management of the disease through application of soil amendments. Besides, field experiment conducted on integrated management and varietal response to stem rot incidence. The late leaf spot was the most prevailing disease which attained a maximum score of 7, a week before harvest. The stem rot incidence initiated 40 DAS and recorded a maximum 7.4% infection up to pod formation and maturity stage of the crop. The weather parameters as a whole contributed about 48.7% to disease development in Kharif, 2017; where minimum temperature solely contribute to 80% to disease development. During Rabi-summer 2017-18, weather parameters as a whole contributed about 62.2% to stem rot development. The maximum and minimum temperature and number of rainy days contributed 38%, 24% and 22% to disease development respectively. Out of eleven number of fungicides experimented through poison food technique; Carbendazim+Mancozeb at 0.2%,Azoxystrobin+Tebuconazole at 0.1%,Azoxystrobin+Mancozeb at 0.1% and triazole group of fungicides viz.Tebuconazole,Propiconazole and Hexaconazole recorded 100% inhibition of the test pathogen. Antagonist Trichoderma harzianum was the most efficacious with 74.4% mycelial growth inhibition,87.1% sclerotial inhibition followed by T.viride with 70.6% mycelial growth inhibition and 85.2% sclerotial inhibition. Out of several organic amendments tried through a pot culture experiment, the FYM enriched T.viride(0.1%) recorded the least mortality of plants due to Sclerotium pathogen(6.7% ).The integrated management approach in field revealed that deep summer ploughing with MB plough+basal application of T.viride@4kg/ha enriched with 50 kg FYM+seed treatment with Tebuconazole@1.5g/kg of seed followed by PGPR @6g/kg seed followed by soil application of Trichoderma @4 kg/ha enriched in 250 kg FYM per ha at 35 and 70 DAS was found to be the best treatment which increased the germination by 24.9%,reduces stem rot by 65.9% and increased the yield by 38.7% when compared to control, with ICBR of 8.03. Out of the prevailing varieties cultivated in Odisha, eight varieties were taken to find their response to stem rot incidence.It was evident that, the variety Smruti was the best with 71.6% reduction in disease and 32.4% increase in yield when compared over the susceptible local check TMV-2.However TAG-24, TG 38B and K6 may be considered as the next best varieties reducing the disease by 63.6%,68.9%,55.4% and increasing the yield by 34.2%,28.8% and 29.9% respectively.
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Th 5430
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